Advanced modeling and design of ion-exchanged glass waveguides and devices

Abstract

Glass waveguide devices fabricated by ion exchange have evolved to the point where conventional assumptions of waveguide symmetry and mutual independence are no longer valid. The modeling of ion-exchanged waveguide devices is far more complicated compared to, e.g., silica on Si waveguide devices. For example, during field-assisted ion exchange processes, the nonhomogeneity of ionic conductivity in the vicinity of the waveguide results in a time-dependent perturbation of the electric field. Previous studies have shown that the depth and vertical symmetry of buried waveguides are affected by the field perturbation. In this work, we describe an advanced modeling tool for guided-wave devices based on ion-exchanged glass waveguides. The effect of field perturbation, due not only to the conductivity profile, but also to the proximity of adjacent waveguides or partial masking during a field-assisted burial are accounted for. A semivectorial finite difference method is then employed to determine the modal properties of the waveguide structures.